The present invention relates to an additive for organic resin and an organic resin composition. More specifically, the present invention relates to an additive for organic resin capable of imparting superior water repellency and surface lubricity to organic resin, and to an organic resin composition possessing superior water repellency and surface lubricity.
It is known in the art to add liquid organopolysiloxanes to organic resins in order to impart water repellency and surface lubricity thereto and it is known to add powdery materials made up of the aforementioned organopolysiloxanes and inorganic powders (see Japanese Unexamined Patent Application Publication No. Hei 03(1991)-054236, Japanese Unexamined Patent Application Publication No. Hei 03(1991)-134050, and Japanese Unexamined Patent Application Publication No. 10(1998)-330617) in order to improve their compoundability. Although dimethylpolysiloxanes are typically used as the liquid organopolysiloxanes, they either cannot impart sufficient water repellency and surface lubricity to organic resins, or cause poor external appearance when resins are molded. In particular, liquid organopolysiloxanes with silicon-bonded hydrogen atoms have been disclosed in Japanese Unexamined Patent Application Publication No. 03(1991)-134050 and Japanese Unexamined Patent Application Publication No. 10(1998)-330617, but the above publications do not imply that the use of such liquid organopolysiloxanes can eliminate the above-mentioned problems.
It is an object of the present invention to provide an additive for organic resin capable of imparting superior water repellency and surface lubricity to organic resin and an organic resin composition possessing superior water repellency and surface lubricity.
The present invention is an additive for organic resin comprising a powder comprising (A) a liquid organopolysiloxane having at least 0.001 wt % of silicon-bonded hydrogen atoms and at least 50 dimethylsiloxy repeating units and (B) an inorganic powder; and an organic resin comprising the additive.
The present invention is an additive for organic resin comprising a powder comprising (A) a liquid organopolysiloxane having at least 0.001 wt % of silicon-bonded hydrogen atoms and at least 50 dimethylsiloxy repeating units and (B) an inorganic powder; and an organic resin comprising the additive.
First of all, detailed explanations are provided regarding the additive for organic resin. Component (A) is a liquid organopolysiloxane used to impart water repellency and surface lubricity to organic resin and it contains at least 0.001 wt %, preferably at least 0.005 wt %, of silicon-bonded hydrogen atoms. This is due to the fact that when the content of silicon-bonded hydrogen atoms is below the above-mentioned lower limits, the moldability of the organic resin composition may decrease. In addition, although there are no particular limitations concerning the upper limit of the content of silicon-bonded hydrogen atoms in component (A), preferably, it is not more than 1.5 wt %, more preferably, not more than 1 wt %, and, especially preferably, not more than 0.5 wt %. This is due to the fact that when the content of silicon-bonded hydrogen atoms exceeds the above-mentioned upper limits, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition. Component (A) is also characterized in that the number of dimethylsiloxy repeating units contained therein is at least 50, preferably at least 100, and especially preferably at least 200. This is due to the fact that when the number of dimethylsiloxy ((CH3)2SiO) repeating units is below the above-mentioned lower limits, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition. Organosiloxy repeating units other than the dimethylsiloxy repeating units in component (A) are exemplified by methylphenylsiloxy ((CH3)C6H5SiO), diphenylsiloxy ((C6H5)2SiO), methylhydrogensiloxy ((CH3)HSiO), methylsiloxy (CH3SiO), and phenylsiloxy (C6H5SiO). In addition, although there are no limitations concerning the viscosity of component (A) at 25xc2x0 C., preferably, the viscosity is 40 to 100,000,000 mPaxc2x7s, more preferably 50 to 1,000,000 mPaxc2x7s, and especially preferably 100 to 1,000,000 mPaxc2x7s. This is due to the fact that if the viscosity at 25xc2x0 C. is below the lower limit of the above-mentioned ranges, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition, and if it exceeds the upper limit of the above-mentioned ranges the compoundability of component (B) tends to decrease.
There are no particular limitations concerning the molecular structure of component (A), which can be, for example, linear, branched, linear with partial branching, cyclic, or resin-like. Component (A) is exemplified by liquid organopolysiloxanes described by general formula 
In the above formula, R1 represents a monovalent hydrocarbon group or a hydrogen atom and R2 represents a hydrogen atom or a monovalent hydrocarbon group exclusive of methyl, with at least one of R1 and R2 in the molecule representing a hydrogen atom. The monovalent hydrocarbon groups of R1 are exemplified by methyl, ethyl, propyl, and other alkyl groups; phenyl, tolyl, and other aryl groups; and vinyl, allyl, and other alkenyl groups. The monovalent hydrocarbon groups represented by R2 are exemplified by ethyl, propyl, and other alkyl groups; phenyl, tolyl, and other aryl groups; and vinyl, allyl, and other alkenyl groups. R3 is a monovalent hydrocarbon group exemplified by the same groups as R1. The subscript m in the above formula is an integer of at least 50. The subscript n in the above formula is an integer of 0 or greater, and when all R1 in the formula are monovalent hydrocarbon groups, n is an integer of at least 1.
Component (A) is exemplified by the following liquid organopolysiloxanes. The subscript m in the formulas is the same as above, subscript p is at least 1, and subscript q is at least 1. 
The inorganic powder of component (B) is exemplified by silica, alumina, magnesia, iron oxide, titania, zinc oxide, and other metal oxides; magnesium hydroxide, aluminum hydroxide, hydrotalcite, calcium aluminate hydrate, barium hydroxide, hard clay and other metal hydroxides; and, in addition to the above, calcium carbonate, calcium silicate, barium sulfate, talc, mica, clay, boron nitride, magnetite sand, glass beads, glass flakes, glass microballoons, diatomaceous earth, or powders consisting of metal, with metal oxide powders being especially preferable. Among such metal oxide powders, silica powder is particularly preferable. Such silica powder is exemplified by dry process silica (fumed silica) powder, wet process silica (precipitated silica) powder, fused silica powder, and crystalline silica powder. Although there are no limitations concerning the average particle size of component (B), preferably, it is not more than 100 xcexcm, and, especially preferably, not more than 10 xcexcm. In particular, in case of silica powder, its BET specific surface area is preferably at least 20 m2/g, more preferably at least 50 m2/g, and especially preferably at least 100 m2/g.
Although there are no limitations concerning the content of the above-described component (B) in the additive for organic resin of the present invention, preferably its content is 50 to 250 parts by weight, more preferably 50 to 200 parts by weight, and especially preferably 75 to 150 parts by weight per 100 parts by weight of the above-described component (A). This is due to the fact that when the content of component (B) is below the lower limit of the above-mentioned ranges, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition, and when it exceeds the upper limit of the above-mentioned ranges it is difficult to grind it into powder for use in the additive for organic resin.
The additive for organic resin of the present invention is prepared by mixing and pulverizing component (A) and component (B). One of the methods used to mix component (A) and component (B) is, for example, a method where component (B) is subjected to agitation while component (A) is added to it. The agitator used at such time is preferably a mixer capable of high-speed shear, for example, a Henschel mixer, a Flowjet mixer, etc. The average particle size of the thus prepared additive for organic resin, which is a powder exhibiting excellent miscibility with organic resins, is preferably 0.1 to 500 xcexcm.
Next, detailed explanations are provided regarding the organic resin composition of the present invention. The organic resin composition comprises (I) an organic resin and (II) an additive for organic resin comprising a powder comprising (A) a liquid organopolysiloxane having at least 0.001 wt % of silicon-bonded hydrogen atoms and at least 50 dimethylsiloxane repeating units and (B) an inorganic powder.
The organic resin of component (I) is exemplified by thermosetting organic resins and thermoplastic organic resins. The thermosetting organic resins are exemplified by phenolic resin, formaldehyde resin, xylene resin, xylene-formaldehyde resin, ketone-formaldehyde resin, furan resin, urea resin, imide resin, melamine resin, alkyd resin, unsaturated polyester resin, aniline resin, sulfonamide resin, silicone resin, epoxy resin, and mixtures of two or more resins mentioned above. The thermoplastic resins are exemplified by polyethylene resin, low-density polyethylene resin, high-density polyethylene resin, ultra-high molecular weight polyethylene resin, polypropylene resin, polymethylpentene resin, ethylene-(meth)acrylate copolymer resin, ethylene-vinyl acetate copolymer resin, and other polyolefin resins; polymethylmethacrylate resin, and other acrylic-based vinyl resins; polystyrene resin, high-impact polystyrene resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, acrylonitrile-acrylic rubber-styrene copolymer resin, acrylonitrile-ethylene-propylene rubber-styrene copolymer resin, and other styrenic-based vinyl resins; polyvinyl acetate resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polytetrafluoroethylene resin, and other vinyl-based resins; polybutylene terephthalate resin, polyethylene terephthalate, and other polyester resins; Nylon 6, Nylon 66, Nylon 10, Nylon 610, Nylon 11, Nylon 12, and other polyamide resins; polyacetal, and other polyoxyalkylene resins; and, in addition to the above, polycarbonate resin, modified polyphenylene ether resin, polyvinyl acetate resin, polysulfone resin, polyether sulfone resin, polyphenylene sulfide resin, polyallylate resin, polyamideimide resin, polyetherimide resin, polyether ether ketone resin, polyimide resin, liquid polyester resin, thermoplastic resin elastomers thereof, and mixtures of two or more resins mentioned above. Polyolefin resin, polyacetal resin, polyester resin, and other olefin-based and ester-based thermoplastic resin elastomers are preferable as component (I) because they impart sufficient water repellency and surface lubricity and are amenable to injection molding and extrusion molding.
The additive for organic resin of component (II), which is used for imparting sufficient water repellency and surface lubricity to the organic resin composition, is a powdery material comprising the aforementioned component (A) and the aforementioned component (B).
Although there are no particular limitations concerning the content of the aforementioned component (II) in the organic resin composition of the present invention, preferably it is 0.01 to 50 parts by weight, and especially preferably 0.1 to 50 parts by weight per 100 parts by weight of component (I). This is due to the fact that it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition when the content of component (II) is below the lower limit of the above-mentioned ranges, and the moldability of the organic resin composition may decrease if it exceeds the upper limit of the above-mentioned ranges.
Other optional components may be combined with the organic resin composition of the present invention in order to adjust its moldability, surface lubricity, mold release properties and the like. Such optional components include calcium carbonate, mica, talc, glass fiber, carbon fiber, and other inorganic fibers; dimethylpolysiloxane having both terminal ends of the molecular chain blocked by trimethylsiloxy groups, methylphenylpolysiloxane having both terminal ends of the molecular chain blocked by trimethylsiloxy groups, diphenylpolysiloxane having both terminal ends of the molecular chain blocked by trimethylsiloxy groups, methyl(3,3,3-trifluoropropyl)polysiloxane having both terminal ends of the molecular chain blocked by trimethylsiloxy groups, organopolysiloxane resin consisting of (CH3)3SiO1/2 units and SiO2 units, organopolysiloxane resin consisting of (CH3)3SiO1/2 units, (CH3)2(CH2xe2x95x90CH) SiO1/2 units, and SiO2 units, organopolysiloxane resin consisting of (CH3)2SiO units and CH3SiO3/2 units, organopolysiloxane resin consisting of (CH3)2SiO units and C6H5SiO3/2 units, and other organopolysiloxanes; and, in addition to the above, strength improvers, anti-oxidants, UV absorbers, photo-stabilizers, heat stabilizers, plasticizers, foaming agents, nucleating agents, lubricants, anti-static agents, electrical conductivity-imparting agents, pigments, dyes, compatibilizing agents, cross-linking agents, flame retarding agents, fungicidal agents, low profile agents, thickening agents, mold release agents, anti-clouding agents, blooming agents, and silane coupling agents.
The present organic resin composition is prepared by mixing component (I), component (II), and if necessary other components under heating. The temperature, to which the components are heated is at least the melting point of component (I). For example, when the aforementioned component (I) is an amorphous thermoplastic organic resin, the above-mentioned temperature is preferably at least 100xc2x0 C. higher than the glass transition temperature of the resin and less than the decomposition temperature of the resin, and when the aforementioned component (I) is a crystalline thermoplastic organic resin, the above-mentioned temperature is preferably at least 30xc2x0 C. higher than the melting point of the resin and less then the decomposition temperature of the resin. The kneading time at the above-mentioned temperature varies depending on the type of the apparatus used and operating conditions. For example when continuous kneader equipment is used, approximately 1 to 5 minutes is sufficient. Equipment permitting kneading under heating is exemplified by Banbury mixers, kneader-mixers, heated 2-roll mills, and other batch-type or single screw extruders; twin screw extruders, and other continuous mixing equipment. The use of continuous mixing equipment such as extruders is preferable, and the use of twin screw extruders is particularly preferable because of the high kneading efficiency and operating characteristics permitting a more homogeneous dispersion of component (II) in component (I).
The present organic resin composition can be molded by potting, heat transfer pressing, injection molding, extrusion, compression molding, and other methods. Because moldings obtained by injection molding possess excellent water repellency and surface lubricity, they are suitable, for example, for interior and exterior components of automobiles and for exterior components of household appliances, etc. The moldings are especially suitable for interior components of automobiles such as door trimming materials, console panels, and instrument panels. In addition, moldings obtained by extrusion molding are especially suitable for automotive components such as weather strips.